5,312 research outputs found
Resonant tunneling controlled by laser and constant electric fields
We develop the concept of scattering matrix and we use it to perform stable
numerical calculations of resonant tunneling of electrons through a multiple
potential barrier in a semiconductor heterostructure. Electrons move in two
external nonperturbative electric fields: constant and oscillating in time. We
apply our algorithm for different strengths and spatial configurations of the
fields.Comment: 10 pages, 11 figure
A revision of the Lower Cretaceous foraminiferal genus Falsogaudryinella from northwest Europe and Romania, and its relationship to Uvigerinammina
We emend the definition of the foraminiferal genus Falsogaudryinella Bartenstein, 1977 based on
observations of the type species, F. tealbyensis from the Barremian Lower Tealby Clay of
Lincolnshire, U.K. The genus was described by Loeblich & Tappan (1987) as having initial triserial
coiling which reduces to biserial and finally uniserial. However, topotype specimens display high
trochospiral coiling in the microsphaeric generation, with at least four chambers in the initial
whorl. The genus, therefore, does not belong in the family Verneuilinidae, but must be transferred
to the Prolixoplectidae. The wall is solid, non-canaliculate. The connections between chambers are
in the form of tubes that extend from the basal part of the chamber lumina toward a terminal
aperture. This tubular connection is partially separated from the main part of the chamber lumina
by a septum. The presence of this tubular connection in F. tealbyensis is closely analogous to that
observed in the type species of Uvigerinammina Majzon, 1943. The two genera, therefore, are
separated mainly on the basis of cement type, with Falsogaudryinella possessing calcareous cement
and Uvigerinammina organic cement.
We illustrate five species of Falsogaudryinella from the Barremian of Lincolnshire, the U.K.
sector of the Central North Sea, and from the Barremian and the Albian of Romania (F. neagui
Bartenstein, 1981, F. praemoesiana n.sp. F. tealbyensis (Bartenstein, 1956), F. xenogena n.sp. and F.
moesiana (Neagu, 1966)). Our investigations reveal that upper Hauterivian to Barremian specimens
from the North Sea that have been previously regarded as F. moesiana (e.g. King et al., 1989) in fact
belong in a new species, Falsogaudryinella praemoesiana n.sp. A second new species, Falsogaudryinella
xenogena n.sp. is described from the Barremian of the Central North Sea. Evolution within the mid-
Cretaceous Falsogaudryinella group appears to progress by reduction of the terminal uniserial part,
since the coiling in the stratigraphically youngest form (F. moesiana) is predominantly triserial. Our
interpretations of the phylogeny of the Cretaceous Falsogaudryinella and Uvigerinammina lineages
are presented
Catalyzing Privacy Law
The United States famously lacks a comprehensive federal data privacy law. In the past year, however, over half the states have proposed broad privacy bills or have established task forces to propose possible privacy legislation. Meanwhile, congressional committees are holding hearings on multiple privacy bills. What is catalyzing this legislative momentum? Some believe that Europe’s General Data Protection Regulation (GDPR), which came into force in 2018, is the driving factor. But with the California Consumer Privacy Act (CCPA) which took effect in January 2020, California has emerged as an alternate contender in the race to set the new standard for privacy.Our close comparison of the GDPR and California’s privacy law reveals that the California law is not GDPR-lite: it retains a fundamentally American approach to information privacy. Reviewing the literature on regulatory competition, we argue that California, not Brussels, is catalyzing privacy law across the United States. And what is happening is not a simple story of powerful state actors. It is more accurately characterized as the result of individual networked norm entrepreneurs, influenced and even empowered by data globalization. Our study helps explain the puzzle of why Europe’s data privacy approach failed to spur US legislation for over two decades. Finally, our study answers critical questions of practical interest to individuals—who will protect my privacy?—and to businesses—whose rules should I follow
How to make semiconductors ferromagnetic: A first course on spintronics
The rapidly developing field of ferromagnetism in diluted magnetic
semiconductors, where a semiconductor host is magnetically doped by transition
metal impurities to produce a ferromagnetic semiconductor (e.g. Ga_{1-x}Mn_xAs
with x ~ 1-10 %), is discussed with the emphasis on elucidating the physical
mechanisms underlying the magnetic properties. Recent key developments are
summarized with critical discussions of the roles of disorder, localization,
band structure, defects, and the choice of materials in producing good magnetic
quality and high Curie temperature. The correlation between magnetic and
transport properties is argued to be a crucial ingredient in developing a full
understanding of the properties of ferromagnetic semiconductors.Comment: 8 pages; to appear in the special issue 'Quantum Phases at Nanoscale'
of Solid State Communication
Response of deep-water agglutinated foraminifera to dysoxic conditions in the California Borderland basins
Analysis of agglutinated benthic foraminifera from surface samples collected in the San Pedro
and Santa Catalina Basins reveals a predictable relationship between the proportions of morphogroups
with decreasing bottom water oxygen levels and with the TOC content of the surficial sediment.
Living (Rose Bengal stained) foraminiferal faunas from dysaerobic environments display
low diversity and high dominance, suggesting stressed conditions. There is an inverse relationship
between oxygen and the relative abundance of deep infaunal morphogroups.
Samples collected from shallow stations above the oxygen minimum zone are comprised of
epifaunal and shallow infaunal morphotypes. At intermediate depths (~500 m), there is a peak in
the abundance of suspension-feeding and "climbing" forms (watchglass-shaped trochamminids
attached to Rhabdammina). Specimens from intermediate stations display the largest overall size.
Deeper in the San Pedro Basin the living fauna is dominated by a small, flattened, tapered,
species that is interpreted as having a deep infaunal microhabitat. In the dysaerobic environments
off California the greatest degree of faunal change occurs when bottom water dissolved oxygen
values drop from 0.5 ml/l to 0.2 ml/l.
The effect of TOC content on the benthic fauna is demonstrated at two stations from the same
depth in the San Pedro Basin. The station with the higher TOC content (4.2% vs. 2.9%) contains
greater proportions of the small, deep infaunal morphotype. These faunal changes may be
attributed to differences in the depth of the oxygenated zone within the sediment surface layer.
Agglutinated faunas from areas that experience seasonal anoxia are comprised of a large
proportion of opportunistic forms such as Reophax and Psammosphaera. These are the same taxa
that colonised abiotic sediment trays in a recolonisation experiment in the Panama Basin. This
study further demonstrates that agglutinated foraminiferal morphotypes respond in a similar
manner to calcareous benthic foraminifera in dysaerobic environments
When the Default Is No Penalty: Negotiating Privacy at the NTIA
Consumer privacy protection is largely within the purview of the Federal Trade Commission. In recent years, however, the National Telecommunications and Information Administration (NTIA) at the Department of Commerce has hosted multistakeholder negotiations on consumer privacy issues. The NTIA process has addressed mobile apps, facial recognition, and most recently, drones. It is meant to serve as a venue for industry self-regulation. Drawing on the literature on co-regulation and on penalty defaults, I suggest that the NTIA process struggles to successfully extract industry expertise and participation against a dearth of federal data privacy law and enforcement. This problem is most exacerbated in precisely the areas the NTIA currently addresses: consumer privacy protection around new technologies and practices. In fact, industry may be more likely to see the NTIA process as itself penalty-producing and, thus, be disincentivized from meaningful participation or adoption
The Right to Explanation, Explained
Many have called for algorithmic accountability: laws governing decision-making by complex algorithms, or AI. The EU’s General Data Protection Regulation (GDPR) now establishes exactly this. The recent debate over the right to explanation (a right to information about individual decisions made by algorithms) has obscured the significant algorithmic accountability regime established by the GDPR. The GDPR’s provisions on algorithmic accountability, which include a right to explanation, have the potential to be broader, stronger, and deeper than the preceding requirements of the Data Protection Directive. This Essay clarifies, largely for a U.S. audience, what the GDPR actually requires, incorporating recently released authoritative guidelines
Binary Governance: Lessons from the GDPR’s Approach to Algorithmic Accountability
Algorithms are now used to make significant decisions about individuals, from credit determinations to hiring and firing. But they are largely unregulated under U.S. law. A quickly growing literature has split on how to address algorithmic decision-making, with individual rights and accountability to nonexpert stakeholders and to the public at the crux of the debate. In this Article, I make the case for why both individual rights and public- and stakeholder-facing accountability are not just goods in and of themselves but crucial components of effective governance. Only individual rights can fully address dignitary and justificatory concerns behind calls for regulating algorithmic decision-making. And without some form of public and stakeholder accountability, collaborative public-private approaches to systemic governance of algorithms will fail.
In this Article, I identify three categories of concern behind calls for regulating algorithmic decision-making: dignitary, justificatory, and instrumental. Dignitary concerns lead to proposals that we regulate algorithms to protect human dignity and autonomy; justificatory concerns caution that we must assess the legitimacy of algorithmic reasoning; and instrumental concerns lead to calls for regulation to prevent consequent problems such as error and bias. No one regulatory approach can effectively address all three. I therefore propose a two-pronged approach to algorithmic governance: a system of individual due process rights combined with systemic regulation achieved through collaborative governance (the use of private-public partnerships). Only through this binary approach can we effectively address all three concerns raised by algorithmic decision-making, or decision-making by Artificial Intelligence (“AI”).
The interplay between the two approaches will be complex. Sometimes the two systems will be complementary, and at other times, they will be in tension. The European Union’s (“EU’s”) General Data Protection Regulation (“GDPR”) is one such binary system. I explore the extensive collaborative governance aspects of the GDPR and how they interact with its individual rights regime. Understanding the GDPR in this way both illuminates its strengths and weaknesses and provides a model for how to construct a better governance regime for accountable algorithmic, or AI, decision-making. It shows, too, that in the absence of public and stakeholder accountability, individual rights can have a significant role to play in establishing the legitimacy of a collaborative regime
Binary Governance: Lessons from the GDPR’s Approach to Algorithmic Accountability
Algorithms are now used to make significant decisions about individuals, from credit determinations to hiring and firing. But they are largely unregulated under U.S. law. A quickly growing literature has split on how to address algorithmic decision-making, with individual rights and accountability to nonexpert stakeholders and to the public at the crux of the debate. In this Article, I make the case for why both individual rights and public- and stakeholder-facing accountability are not just goods in and of themselves but crucial components of effective governance. Only individual rights can fully address dignitary and justificatory concerns behind calls for regulating algorithmic decision-making. And without some form of public and stakeholder accountability, collaborative public-private approaches to systemic governance of algorithms will fail.
In this Article, I identify three categories of concern behind calls for regulating algorithmic decision-making: dignitary, justificatory, and instrumental. Dignitary concerns lead to proposals that we regulate algorithms to protect human dignity and autonomy; justificatory concerns caution that we must assess the legitimacy of algorithmic reasoning; and instrumental concerns lead to calls for regulation to prevent consequent problems such as error and bias. No one regulatory approach can effectively address all three. I therefore propose a two-pronged approach to algorithmic governance: a system of individual due process rights combined with systemic regulation achieved through collaborative governance (the use of private-public partnerships). Only through this binary approach can we effectively address all three concerns raised by algorithmic decision-making, or decision-making by Artificial Intelligence (“AI”).
The interplay between the two approaches will be complex. Sometimes the two systems will be complementary, and at other times, they will be in tension. The European Union’s (“EU’s”) General Data Protection Regulation (“GDPR”) is one such binary system. I explore the extensive collaborative governance aspects of the GDPR and how they interact with its individual rights regime. Understanding the GDPR in this way both illuminates its strengths and weaknesses and provides a model for how to construct a better governance regime for accountable algorithmic, or AI, decision-making. It shows, too, that in the absence of public and stakeholder accountability, individual rights can have a significant role to play in establishing the legitimacy of a collaborative regime
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